1. Technical Field of the Invention
This invention relates to telecommunication systems and, more particularly, to a policy server and architecture that provides radio network resource allocation rules in a real-time Internet Protocol (IP)-based telecommunications network.
2. Description of Related Art
As wireless networks evolve from primarily circuit-switched technology to IP-based packet-switched technology, networks with substantially more flexibility than current networks will bring new capabilities to consumers. However, converging Internet technology and wireless telecommunications technology is introducing new problems and new requirements on the wireless network. In circuit-switched networks, an application is assigned fixed-network resources (for example, a 64-kbit circuit) regardless of the amount of bandwidth actually required by that particular application. In many cases, the application may not fully utilize the allocated bandwidth, and network resources are wasted. Alternatively, if the application needs more bandwidth than the allocated amount, it may not be able to get it, and the application cannot request more bandwidth after it has started its execution.
As an example, a call may be placed from a mobile subscriber in Montreal to a mobile subscriber in Sweden. The circuit-switched call is routed from the cellular provider network in Montreal, through a domestic wireline provider, through an international provider, through one or more wireline providers in Europe, and finally to the Swedish mobile provider. Various gateways and switches contribute to establishing the end-to-end circuit-switched connection, which has to go through many different domains. Once the connection is established, there is no negotiation over bandwidth required for any particular application because the connection is fixed at 64 kbps. This is often a wasteful utilization of bandwidth capacity since a 64-kbps link is not required for a voice call; a voice call can be carried with excellent voice quality on a link operating, for example, at only 9.6 kbps.
The Application Performance Rating Table below further illustrates this problem by showing the amount of bandwidth required for different types of applications in order to achieve certain levels of Quality of Service (QoS). For example, if high quality video is carried over an ISDN link at 128 kbps, the end user sees jerky, robotic movement (fair). However, if the video is provided at 384 kbps, the quality of the video is much better. At the other end of the performance spectrum, a voice call can be carried at 9.6 kbps and still have excellent voice quality. For efficient use of network resources, a control mechanism is needed to ensure that the right amount of bandwidth is provided to deliver the requested QoS without wasting excess bandwidth.
In packet-switched IP-based networks, the amount of assigned bandwidth is not fixed. An application can request specific network resources, and then renegotiate the allocated network resources during its lifetime. In an integrated network combining a fixed IP network with a radio access network, a major problem is how to provide this type of flexibility in the radio access portion of the network.
Another problem is that wireless access technologies such as xe2x80x9cEnhanced Data for Global System for Mobile Communications (GSM) Evolution (EDGE)xe2x80x9d. Wideband Code Division Multiple Access (Wideband CDMA or WCDMA), CDMA 2000, Wireless Local Area Networks (WLAN), or Bluetooth wireless radio links are more subject to transmission errors than conventional fixed networks. Consequently, integration of the radio access portion with the more reliable fixed IP network is introducing new problems. For example, when using the Transmission Control Protocol (TCP) on a fixed IP network, lost packets due to transmission errors are retransmitted. Therefore, if someone in Australia is establishing a connection to a third generation (3G.IP) mobile terminal in North America using TCP, and some transmission errors occur on the radio link channel, TCP attempts to retransmit the data. The retransmission will occur from the originating point in Australia rather than locally between the base station and the mobile terminal. Therefore, an extra load is placed upon the entire network because of transmission problems in the radio portion.
An additional problem arises because the bandwidth over radio channels is typically more limited compared to the rest of the IP Access, EDGE, and core network. Therefore, some mechanisms are required in order to avoid unnecessarily carrying packets all the way from an origination point to a mobile terminal in a wireless network when the wireless network is not able to transport these packets to and from the mobile terminal. This is especially true when real-time applications such as Voice-over-IP (VoIP) are being utilized.
When a Voice-over-IP (VoIP) call is established across different domains in a packet-switched IP network, the parties involved in the call can change the bandwidth allocated to the call in the middle of the call. In other words, the characteristics of the bearer can be changed while the call is in progress. An example of the problem that this can present can be illustrated utilizing a scenario in which a real-time stream such as video is being sent from a mobile terminal in Montreal to a receiving mobile terminal in Sweden. During the call, the mobile subscriber receiving the transmission in Sweden requests that the sender increase the bandwidth, for example, to go from 8-bit color to 24-bit color to improve the accuracy of the received video. When the request is received in the sender""s mobile terminal in Montreal, the terminal responds by increasing the bit rate to carry 24-bit color. The operators of the intermediate domains also increase the bandwidth allocation to the call to enable the additional data to be delivered. However, if radio resources in the receiver""s radio access network in Sweden are totally occupied, the extra information cannot be delivered to the receiving mobile terminal, and is discarded. This is a highly inefficient use of system resources, and the carriers who provided the bandwidth to carry the information all the way from Montreal to the radio network in Sweden still want to be paid even though the information was discarded at the end.
There are no known prior art teachings of a solution to the aforementioned deficiencies and shortcomings. The Internet Engineering Task Force (IETF) has proposed a Policy Framework and Architecture for third generation (3G) wireless Internet Protocol (IP) networks and the Internet, the purpose of which is to establish the real-time network control that is necessary to transform the Internet from a xe2x80x9cbest effortsxe2x80x9d data network to a more reliable, real-time network. There are two releases of the proposal for 3G systems, but neither of the releases addresses the issue of providing policy rules for the control of radio access network resources.
The first release, referred to as 3GPP Release 99, introduces some new radio access technology such as Wideband CDMA and EDGE. Wideband CDMA introduces not only a new radio technology, but also Asynchronous Transfer Mode (ATM) technology in the radio access portion of the network. In the Wideband CDMA radio network controller, two interfaces are supported. One is called Iu-cs which is circuit-switched toward the current circuit-switched network, and one is called Iu-ps which is packet-switched toward the General Packet Radio Service (GPRS) wireless IP network. All the real-time voice and data still goes through the circuit-switched network, and data goes through the best-efforts GPRS network. There is no integrated real-time network.
In the second 3G release called 3GPP Release 00, a real-time IP network is envisioned with all the infrastructure to carry real-time applications with equal or getter quality than circuit-switched networks. Policy rules are provided to a Bandwidth Broker (BB) regarding the resources of the fixed network, but not for the wireless access portion.
It would be advantageous, therefore, to have a network architecture that includes a policy server that provides radio network resource allocation rules to a BB. Additionally, the architecture would enable BBs to pass resource information to BBs in other domains thereby providing an indication of the end-to-end bandwidth capacity of a connection, including the radio access portion, to each BB involved in a connection. Thus, this solution would prevent the sending of data that cannot be carried through to the destination. The present invention provides a policy server and architecture that achieves these objectives.
In one aspect, the present invention is a policy server for providing radio network resource allocation rules to a Policy Decision Point (PDP) in a third generation (3G) wireless Internet Protocol (IP) network. The policy server includes means for determining a level of availability of radio network resources, an interface toward the PDP, and means for determining whether the level of availability of radio network resources is sufficient to satisfy the received requests for resources. The policy server receives queries from the PDP regarding the availability of radio network resources to satisfy requests for resources, and sends responses to the PDP indicating whether the requested resources are available.
In another aspect, the present invention is a Bandwidth Broker (BB) that functions as a PDP in a radio network access portion of an integrated IP network. The BB includes a user/application interface for receiving a call request from a user, or an inter-BB interface for receiving a request from another BB. The BB also includes means for determining radio network resources required to satisfy the received call request, a policy server interface toward a Radio Network Server (RNS), and an intra-domain interface toward an edge router for sending an approval or a denial for the requested resources. The BB sends queries to the RNS regarding the availability of radio network resources to satisfy the received call request, and receives responses from the RNS indicating whether the requested resources are available or allowed.
In yet another aspect, the present invention is a policy architecture for an integrated 3G wireless IP network having a radio access domain and an IP-based domain. The policy architecture includes a BB that functions as a PDP in each domain, a plurality of edge routers in each domain that interface with the BB and function as Policy Enforcement Points (PEPs), and a policy server that interfaces with the BB and provides radio network resource allocation rules to the BB.